1. Field of the Invention
The present invention relates to a corrugated board pallet, and more particularly to a pallet constructed from corrugated board sheet such as cardboard for the purpose of storing, loading and unloading industrial products.
2. Description of the Prior Art
Various types of pallets constructed from wood, synthetic resin, metal, or the like have been used to lift and transport industrial products such as common appliances and light-weight machinery by using a forklift vehicle.
In order to conserve natural and economic resources and in response to the difficulty with the disposal of used pallets as industrial waste, in recent years, pallets constructed from corrugated cardboard have gradually been used in place of the pallets constructed from wood, synthetic resin, and metal.
The corrugated cardboard pallet has many advantages over the conventional wooden, synthetic resin, or metal pallet in that shock caused by vibration or falling can be absorbed; the pallet can be reused until worn out; the pallet can be recycled in cases where reuse is difficult or impossible to conserve natural and economic resources; the pallet can easily be disposed as industrial waste and energy for the disposal can be saved; and the weight of the pallet is reduced; and the damage common to other types of pallets by noxious insects and the breeding of bacterium can be reduced; and connecting parts such as nails, bolts and nuts are unnecessary, reducing the possibility of human body injury.
The construction of a pallet using a corrugated cardboard sheet has been proposed in Japanese Patent Publication (Examined) No. Showa 62-36741.
In the conventional pallet disclosed by the document mentioned above, a load carrying member is formed by bending a corrugated cardboard sheet with parallel fork channel bends are formed in the bottom side of the load carrying member in the direction that the forks of a forklift vehicle insert, and a pair of horizontal wooden stiffening planks situated toward the front and rear of the load carrying member perpendicular to the fork channel bends. The pair of wooden stiffening planks extend to both sides of the pallet and attach to the bottom side of the upper surface of the load carrying member. Further, cylindrical supports are located between the wooden stiffening planks and lower surface of the structural reinforcing bends.
In the case of pallets constructed with the structure described above, the wave of the corrugated cardboard which forms channel shaped fork channel bends in the load carrying member in parallel with the direction that the forks of the forklift vehicle insert, and the stiffness of the load carrying member is insufficient. As a result, when a heavy load is applied, the load carrying member can not bear the load so that the center of the load carrying member is prone to collapse. Further, when lifted and transported by the forklift vehicle, the load carrying member bends downward at both ends due to the load on the pallet and forms an arch at the center of the load carrying member, which may also cause the load carrying member to collapse.
Further, the structure of the pallet is rather complicated, the number of manhours required to assemble the pallet is rather high, and the assembly requires many parts, and the number of parts for the pallet increases, resulting in a high production cost.